1. Field of the Invention
The present invention relates generally to an automatic telephone dialing system and more particularly to a repertory dialer system providing automatic dialing of a relatively large number of different stored telephone numbers either by a single manual operation by a user or else by the user searching for a stored name in a name and number memory.
2. Description of the Prior Art
Telephone repertory dialers are accessories that can be connected to standard telephones to automate the dialing of frequently used numbers that are stored in the dialer. Such dialers enable one to initiate a telephone call by depression of a single button. Often such dialers also include features which enable a number once dialed to be remembered so that if the calling party does not answer or if the called line is busy, redialing of that same number may be initiated by the simple actuation of a single button at a later time.
A wide variety of telephone repertory dialers already exist. Examples of such previously proposed dialers are disclosed in the following U.S. Patents:
______________________________________ U.S. PAT. NO. PATENTEE ______________________________________ 3,555,201 Kuehnle 3,670,111 Bukosky, et al. 3,885,108 Zock 3,998,550 Ts'ao 4,029,908 Moseley et al. ______________________________________
The Kuehnle Patent, No. 3,555,201, discloses an electromechanical arrangement wherein a plurality of rotary switches may be set to store, within a unit, the numbers for a number of frequently dialed destinations. On the upper panel of the unit there is a pushbutton corresponding to each of these numbers which may be labeled with the name of the organization or person corresponding to the stored number. By depressing one of these pushbuttons, one causes the associated switch to be scanned such that the number represented by the setting of the switch is transmitted out over the telephone line as touch tones or pulses.
The Bukosky et al. Patent, No. 3,670,111, discloses a more sophisticated arrangement wherein the settable switches are replaced with an electronic memory that may be loaded by typing the numbers in upon a keyboard and storing them within the memory. This apparatus operates similarly to the Kuehnle apparatus but is far simpler to load with numbers since such numbers are simply typed in upon a keyboard rather than set by means of rotating individual switch elements. In addition, Bukosky et al. includes a "last number dialed" memory which preserves a record of the last number that has been dialed so that by pressing the corresponding pushbutton, this number may be redialed again. This last feature is useful in cases where the phone called was busy or did not answer such that redialing can be initiated at a later time by simple actuation of a single button.
The Zock Patent, No. 3,885,108, discloses a modem device for facilitating the interconnection of a computer terminal to a telephone line which has the capacity to store only one number. However, this patent discloses timer means for automatically causing this number to be redialed a number of times if the first attempt to establish communication is unsuccessful.
The Ts'ao Patent, No. 3,998,550, also discloses a repertory dialer having a plurality of buttons. A magnetic drum is used for storing pulse-tone coded reprentations of the digits, and the arrangement is a hybrid electromechanical device.
The Moseley et al Patent, No. 4,029,908, discloses an arrangement that does not have a plurality of pushbuttons on its upper surface, as in several of the arrangements described above. Instead, Mosely et al. discloses a device having a magnetic ribbon stored within it, the upper surface of which is exposed to view and can accept typed or handwritten names and the undersurface of which is suitable for the recording of digits. The Mosely et al. apparatus contemplates capturing the digits typed in on the keyboard in a register and then transferring the contents of the register onto the back of the magnetic strip at a position corresponding to where, on the front of a strip, a name has been written by the operator. By positioning the tape so that a particular name is visible, one can then cause the corresponding set of digits to be scanned off the tape, loaded into a register, and sent out over the telephone lines, either in pulse tone or touch tone format. This device has a very large capacity for names but it requires those names to be listed on the tape in alphabetical order and a slow, linear search of the tape is required to find any particular name. Additionally, it is possible for names to become so compressed adjacent each other on the tape that either the alphabetical order must be violated when new names are added or else the entire loading of the tape with names must be repeated due to lack of room at a particular location on the tape.
A review of the devices disclosed in the above patents indicates that repertory dialers having pushbuttons on their front panels are fairly well known in the art. However, there remains a need for repertory dialers having a much larger capacity and providing an accelerated way in which the number corresponding to a particular name can be found within a memory, retrieved and then used to control the automatic dialing of the number.
In addition, many of the prior art devices disclosed above include complex electromechanical arrangements having many moving parts which can contribute to maintenance problems and also add to the expense of manufacturing such devices. The use of complicated, discreet logic circuits is also evident in the above devices, as is the excessive use of complex logic for converting numbers into a form suitable for storage on a magnetic tape, additional complex logic for reading those tapes, and reading heads and the like which add to the complexity of these devices.